In a current storage network, for example, a storage area network (SAN), as shown in FIG. 1, a server and a storage engine are connected to a switch separately, an end of the storage engine that is connected to the switch is a front end, and a back end of the storage engine is connected to a cabinet. To avoid a single point of failure, two controllers, for example, a controller A and a controller B shown in FIG. 1, are disposed in the storage engine. When a controller A in a storage engine A becomes faulty, the server accesses a disk in the cabinet by using a storage controller B in the storage engine A. However, if both the storage controllers A and B in the storage engine A become faulty, data in a cabinet A connected to the storage engine A cannot be accessed. As a result, reliability of the storage area network is restricted.
In the prior art, a back end of a storage engine is connected to a switch that has a serial attached SCSI (SAS) interface, so that storage controllers are connected by using a cabinet of a SAS switch, and a target cabinet can be accessed by using any storage controller.
However, it is found that a quantity of interfaces of a switch that are used to connect a storage engine and a cabinet is excessively small, for example, a SAS switch has only 16 interfaces, so that a quantity of connected controllers and cabinets is limited; and a length of a cable of the switch is limited, and large-scale expansion cannot be performed, so that a total quantity of capacities of disks that can be connected is limited.